Mill hammer



A. B. SCHREYIBER 2,244,577

MILL HAMMER Jim 3, 1941.

Filed 001:. 20. 1939 Patented June 3, 1941 UNITE ST rr FFlCE 7 Claims.

My invention, which relates to hammer mills, has particular reference to certain new and useful improvements in the grinding hammers used, by which the cost of the hammers is reduced, their life lengthened, and the work they do is improved over that of hammers now in general use.

Further, the invention has for its object to provide a hammer having four positions to which it can be moved to present operative grinding projections to the work and, after these have been worn, the hammer may be reversed and used in four more positions before it shall be worn out and discarded.

Further, it is an object to provide a hammer, formed of suitable material, whose grinding portions may be efiectively hardened Where the wear takes place. It is well known that when a piece of steel, for instance, is heat-treated, the

hardening action penetrates only to a limited depth into the metal (case hardening), whereas with my design of hammer the hardening action penetrates from a number of difierent surfaces, resulting in the necessary working parts becoming hardened through and through.

Other objects will in part be obvious and in part be pointed out hereinafter.

To the attainment of the aforesaid objects and ends the invention still further resides in the novel details of construction, combination and arrangement of parts, all of which will be first fully described in the following detailed description, and then be particularly pointed out in the appended claims, reference being had to the accompanying drawing, in which:

Fig, 1 is an elevational view of a portion of a rotor with one hammer attached.

Fig. 2 is an enlarged side elevation of one of the hammer heads or hammers proper.

Fig. 3 is an edge View of the same.

Fig. 4 is an enlarged central vertical section on the line 4-4 of Fig. 1.

Fig. 5 is a detail side elevation ofa modification.

Fig. 6 is an edge view of the same.

In the drawing, in which like members and letters of reference indicate like parts in all the figures, I is the rotor shaft to which is attached the disc 2 having the holes 4 for the pivots 3 of the radius arms [6, H5, between which the hammer head-plate 8 is held. The hammer head-plate is apertured at 9 to fit the smooth surface of a pin 5, the ends 6 and I of which are screwed into openings, in the arms [6 and It, provided for the purpose (see Figs. 1 and 4).

The plate 8 has a set of four arms I0 equally spaced and separated by radial slots. The outer edges of the arms 10 are square cut and lie from adjacent ones. Each arm Iii is slotted as at l4 to present two side portions I2 and a midportion II. There is also provided a recess 15 or a hole in each arm so designed that portions :1: and y of the metal are of about the same mass as the masses of metal of the side portions i2, thus aiding in the provision of uniformly hardened grinding elements A, B, C, D.

The side grinding portions 12 may have beveled portions l3 on each side face of the hammer to prevent the inner grindings elements B and D from wear until the elements A and C have worn down. Thus when the time arrives for the elements B and D to function, there will have been little Wear on the same and a practically fresh grinding element will be presented.

One of the radius arms has a tongue l'i stamped inwardly to enter a recess or hole IS in the hammer and hold the hammer against turning on its pin 5 While in use.

In Figs. 5 and 6 is shown a slight modification in which the points A and C are laterally extended beyond the portions [2 to give more wearing mass.

From the foregoing description, taken in connection with the accompanying drawing, it is thought the construction and advantages of the invention will be clear to those skilled in the art.

What I claim is:

1. In a grinding mill having a rotatable disc, a pair of radius arms pivoted to said disc, a hammer proper mounted for adjustment rotatably between the outer extremities of said arms, said hammer proper comprising a flat body having a plurality of arm portions each having a flat outer edge provided with slots to divide the arm portions into two side grinding members and a midportion also presenting at its two sides grinding members which are designed to come into action after the respective ones of the two side grinding members have worn down a predetermined distance.

2. In a grinding mill having a rotatable disc, 2. pair of radius arms pivoted to said disc, a hammer proper mounted for adjustment rotatably between the outer extremities of said arms, said hammer proper comprising a fiat body having a plurality of arm portions each having a flat outer edge provided with slots to divide the arm portions into two side grinding members and a midportion also presenting at its two sides grinding members which are designed to come into action after the respective ones of the two side grinding members have worn down a predetermined distance, said arm portions having recesses, and one of said radius arms having a tongue projected into one of said recesses to hold the hammer proper against turning on its axis.

3. In a grinding mill having a rotatable disc, a pair of radius arms pivoted to said disc, a hammer proper mounted for adjustment rotatably between the outer extremities of said arms, said hammer proper comprising a fiat body having a plurality of arm portions each having a fiat outer edge provided with slots to divide the arm portions into two side grinding members and a mid-portion also presenting at its two sides grinding members which are designed to come into action after the respective ones of the two 7 side grinding members have worn down a predetermined distance, said side grinding members having beveled faces at the sides of the hammer proper, said grinding members being hardened to resist wear, said side grinding members being extended to overhang the side edges of the arm portions.

4. In a grinding mill having a rotatable disc, a pair of radius arms pivoted to said disc, a hammer proper mounted for adjustment rotatably between the outer extremities of said arms, said hammer proper comprising a flat body having a plurality of arm portions each having a fiat outer edge provided with elongated slots to divide the arm portions intotwo side grinding members and a mid-portion also presenting at its two sides grinding members which are designed to come into action after the respective ones of the two side grinding members have worn down a predetermined distance.

5. In a grinding mill having a rotatable disc, a pair of radius arms pivoted to said disc, a hammer proper mounted for adjustment rotatably between the outer extremities of said arms, said hammer proper comprising a fiat body having a plurality of arm portions each having a flat outer edge provided with elongated slots to divide the arm portions into two side grinding members and a mid-portion also presenting at its two sides grinding members which are designed to come into action after the respective ones of the two side grinding members have worn down a predetermined distance, said slots at their inner ends being laterally enlarged toward the outer side of the sides of the arms.

6. In a grinding mill having a rotatable disc, radius arms pivot-ed to said disc, a hammer proper mounted between the outer extremities of said arms and comprising a flat body proper having at least one arm portion the outer end face of which is a plane surface, said arm portion having two elongated slots entering from said outer end face and extending inwardly toward the body proper and spaced apart, thereby providing two side grinding members and a middle portion and defining at least four grinding corners one on each outer side of each side grinding member and one on each side of the middle portion, said slots at their inner ends being laterally enlarged, thereby reducing the width of the side grinding members where they join said body proper, by virtue of all of which the grinding portions of the side grinding members will be worn down before the grinding portions of the middle grinding members become substantially worn down.

7. In a grinding mill having a rotatable disc, radius arms pivoted to said disc, a hammer proper mounted between the outer extremities of said arms and comprising a flat body proper having at least one arm portion the outer end face of which is a plane surface, said arm portion having two elongated slots entering from said outer end face and extending inwardly toward the body proper and spaced apart, thereby providing two side grinding members and a middle portion and defining at least four grinding corners one on each outer side of each side grinding member and one on each side of the middle portion, said slots at their inner ends being laterally enlarged, thereby reducing the width of the side grinding members where they join said body proper, by virtue of all of which the grinding portions of the side gringing members will be worn down before the grinding portions of the middle grinding members become substantially Worn down, said arm portion having a rectanguiar recess in the face of the middle portion.

ALLEN B. SCI-IREIBER. 

